So, it seems like the upgrade of OpenCV to version 1.3 has busted the OpenCVFrameGrabber on the RasPI3.  Where, I don't have a fix for this issue yet, I do have a work around for the problem.  Here's the steps to get OpenCV working on the RasPI3 on the latest build  (until we sort the javacv 1.3 issue.)

  1. Download the latest myrobotlab.jar
  2. run java -jar myrobotlab.jar and install all services
  3. exit myrobotlab
  4. copy all of the jar files from the javacv 1.1 and overwrite the files in myrobotlab/libraries/jar from here:  https://github.com/MyRobotLab/repo/tree/develop/org.bytedeco.javacv/1.1
  5. start myrobotlab
  6. start an open cv service
  7. click capture...

Bingo!  video worky on the raspi again!

 

Mats

7 years 4 months ago

Since it's now possible to use FFmpeg in OpenCv, I wanted to make a comparision between the two alternatives.

So first I tested the 2365 build, without any changes.

Start OpenCV. Then select FFmpeg as input, mark the radibutton file and enter /dev/video0 as filename. Press capture.

After that I added 4 filters. PyramidDown, Gray, Flip and Facedetect. As you can see in the image I got about 2fps. Not too bad. But latency is a real problem. It takes around 10 seconds from something is put in front of the camera uuntil it becomes visible. Doh.

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

Then I tested the procedure above to see what performance OpenCv would result in. 

Open OpenCv. Press capture.

The add the same four filters to get comparable results.

The resulting fps is also about 2 seconds. However OpenCv performs much better when it comes to latency. I get somewhere between 1-2 seconds latency. 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

So the conclusion is: Use kwatters procedure above, unless you want to us the FFmpeg input for some other reason, because FFMpeg will no longer work after replacing the jar files.